1. Field of the Invention
The present invention relates to a spinning apparatus, and more particularly, to a spinning apparatus for wet-etching a wafer.
2. Description of the Related Art
Generally, wet etching can be performed using wet benches, which are used to wet etch a plurality of wafers at the same time, or single water processors, which are used to wet etch one wafer at a time. Wet benches or batch wafer cleaners can process a large quantity of wafers, but, unfortunately, they occupy large areas. Also, when problems occur in the etching process, it is very likely that an entire batch of the wafers will have defects.
On the other hand, while single wafer processors require a long time to etch many wafers, they occupy a small area. Also, even when problems occur in the etching process, only one wafer is affected. Therefore, single wafer processors have become more prevalent than wet benches.
The most common form of the single wafer processor is a spinning apparatus.
FIG. 1 is a perspective view of a conventional spinning apparatus, and FIG. 2 is a plan view of the spinning apparatus of FIG. 1.
Referring to FIGS. 1 and 2, the conventional spinning apparatus includes a spin table 1 on which a wafer is placed, and a rotation unit 3 used to rotate the spin table 1. A back nozzle 5 to spray an etching chemical into a backside of the wafer is disposed in the center of the spin table 1. A plurality of fixing pins 2 are disposed on an edge of the spin table 1 to fix the wafer.
The rotation unit 3 includes a motor (not shown) used as a driving source, and a rotation shaft 4 providing a torque produced by the motor to the spin table 1.
In the conventional spinning apparatus, the amount of etching chemical sprayed to the backside of the wafer varies from region to region on the wafer. This causes a problem of a non-uniformly etched wafer backside.
In addition, the entire spin table 1 of the conventional spinning apparatus rotates, making it difficult to apply an etching chemical to a bevel of the wafer. Thus the bevel of the wafer cannot be easily etched.